Car shoppers should expect to see the revised ELR, which was all-new for the 2014 model year, at dealerships in the first half of next year.

The changes are designed to make the ELR more competitive against a growing list of rivals, including the BMW i3, Porsche Panamera SE Hybrid and Tesla Model S. The ELR is a premium version of the Chevrolet Volt.

Cadillac?s niche specialty car has had a slow start out of the gate.

GM sold 774 ELRs in the U.S. from January through August, according to the carmaker.

The ELR starts at $75,995, including a $995 destination charge. Pricing is before a federal tax credit of up to $7,500 and any state or local tax credits.

Some Cadillac dealers have been offering incentives as high as $30,000 in order to boost sales of the ELR, according to industry analysts.

"Inventory levels have come down quickly with these incentives, so I would expect them to start scaling back fairly soon," Joe Langley, a principal analyst for IHS Automotive, told Edmunds.

Caldwell said some of the large discounts were applied to "demo models" of the ELR with several hundred miles on the odometer.

Car shoppers will note that there is no 2015 Cadillac ELR. Caldwell explained that this is a "technicality" based on when the car debuted around January 1, 2014.

"The car is still on sale," he said. "The factory produced most of the cars that would satisfy U.S. distribution."

ELR production has been halted due to inventory and an extensive makeover of the Detroit-Hamtramck plant where the ELR is built, along with other GM cars, including the Chevrolet Impala.

Caldwell said the plant is scheduled to resume production around Thanksgiving.

"ELR builds will resume after the first of the year," he said.

Edmunds says: Any improvements that can be made to the current model will be a welcome change as it is struggling to prove that it deserves its $76,000 asking price.